Stoker heating apparatus



Nov. 11, 1941. F. D. YARICK 2,252,073

STOKER HEATING APPARATUS I Filed April 3, 1939 2 Sheets-Sheet l ZSnnentor flora D. FIR/CK.

Nov. 11, 1941. F. D. YARICK STOKER HEATING APPARATUS Filed April 3, 1959 2 Sheets-Sheet 2 iiiRiiifi ii. 5 3 r 1: I E E E x: A N k k Patented Nov. 11, 1941 UNITED STATES PATENT OFFICE 2,262,078 7 STOKER, HEATING APPARATUS Floyd n. .Yarick, Detroit, Mich. Application April 3, 1939, Serial No. 265,653

3 Claims.

This invention relates generally to heating apparatus and more particularly to fuel stokers.

It is an object of the present invention to provide a new and improved stoker type heating apparatus in which injury to and destruction of the fuel feed screw by the fire is prevented.

Another object of the invention is to provide a new and improved stoker heating apparatus in whicha motor blower unit is readily removable from the apparatus as a unitary structure.

Other objects of the invention will become apparent from the following description taken in connection with the accompanying drawings, in which Figure 1 is a perspective view of my improved stoker type heating apparatus;

Fig. 2 is a plan view of the apparatus with parts broken away and in section;

Fig. 3 is a view shown in section of parts of the apparatus, and

Fig. 4 is a detail view taken along the line and in the direction of the arrows 4-4 of Fig. 3.

Referring to the drawings by characters of reference, the numeral l designates a furnace which may be any suitable type adapted to receive therein a stoker retort H to which fuel is delivered by a feed screw l2 driven by a motor l3. The motor l3 also drives a blower l4 and is preferably controlled by a room thermostat, designated generally by the numeral l5. The motor l3 and blower l4 are relatively laterally positioned and are located on the opposite side of the furnace ID from the source of supply of fuel or from a bin or hopper.

The retort II is of sectional construction and, in the present instance, comprises .in general, a base or lower section [6, an intermediate section l1 and a top section l8. A horizontally extending duct opens at its opposite ends through hollow bosses 2| and 22 which are formed integral with the base, the hollow boss 2l constituting the fuel inlet to the retort. Connected to'the retort inlet 2| is a duct or conduit 23 which slidably adjustably receives a fuel supply duct 24 through which the feed screw l2 extends, the supply duct 24 being supported at its inlet end by a suitable support 25.

The feed screw l2 extends into the retort fuel supply duct 20 from which an upwardly directed central passage 21 defined in part by the intermediate section I! opens through the top wall 28 of the upper retort section l8. Preferably, the feed screw I2 is provided with a thread 29 arranged to move fuel into the retort,

and beyond the vertical passage the screw is 55 a branch 43 connected to preferably provided with a reverse thread 30 which in operation of the feed screw cooperates with the thread 29 to urge fuel up through the passage 21.-

I The; feed screw extends through the retort fuel duct 20 and terminates adjacent the outer end of the hollow boss 22 in a circular plate 3! which is provided to prevent any substantial amount ofair delivered by the blower 13 from passing into the retort via the duct 20. The feed screw thread is provided on a shaft 32 which is hollowor tubular so that air from the blower l3 may flow therethrough for the purpose of keeping .the shaft, particularly that portion of it within the retort, relatively cool so that the fire will not -injure or burn out the shaft. Connected to thehollow boss 22 is a duct or conduit section 33 through which the hollow screw shaft 32 extends and al 0 extends through a gear housing 34 having a'vertical wall 35 wherein a thrust bearing 36 is provided for the shaft. Fitted over the outer end of the screw shaft 32, a coupling member 31 is provided with a reducedend portion 38 which may be a square shank to be received in one end of a cooperating coupling sleeve 40, the other end of the coupling sleeve loosely receiving the drive shaft 4| of the motor l3. The shaft32and coupling member 31 may be provided with aligning transverse apertures to receive a pin 4Ia to connect the parts together.

, Enclosingthe coupling members and shaft is a duct or conduitv 42 which has one end bolted as at 42a to the casing 34, the duct 42 having the motor housing and having a branch 44, connected to the outlet of the blower l3. The hollow coupling member is provided with a transversely extending bore or bores 45 through which air enters from duct 44 for flow longitudinally and within the hollow shaft-.32 vto reduce the temperature thereof.

Within the housing 34, a drive gear 41 secured to'the shaft'32 meshes with and drives a gear 48 on a shaft 50 which extends parallel to the screw-shaft 32, the driven shaft 50 extending into the retort passage 2'! transversely thereto. The inner :end of the shaft 50 may be reduced to receive a bushing 5| which may be retained in a recess 52 formedby the base I6 andintermediate retort section I! seating on the base. Within the retort passage 21, the shaft 5U'has a square portion 53, in the present instance, and secured in andto the shaft portion 53 is a pair of spaced pins or rods 54. which extends transversely of and through the shaft with their opposite ends 2 projecting therefrom. These rods constitute agitators for agitating the fuel so as to break up the fuel and prevent clinker formations.

As shown in Fig. 2, the hollow boss 22 is divided by a central duct portion 55 into two air ducts 56 and these air ducts 55 lead into an annular air chamber 51 of the retort, the air chamber 51 surrounding the fuel passage 21 to reduce the temperature of the retort and from which chamber air is supplied through a plurality of air outlets 58 to the fire to provide for good combustion. Sorewthreaded into the duct 20,

a hollow tube extends up into the air chamber for the passage of air therefrom into the duct 20 at a point between the duct fuel inlet 2| and the vertical passage 21 to build up a pressure in the duct 29 to aid the fuel pack in preventing back smoke through the fuel supply duct, Also in this inlet portion of duct 20, the hollow shaft 32 is provided with spaced outlets 60 for the escape of air therefrom into the fuel supply duct to thereby further aid in building up a resisting air pressure to back smoke.

As shown in Figs. 3 and 4, the housing 34. is provided with spaced air openings or passages which are controlled by dampers 61 mounted on a common shaft 62 which is journalled for rotation in the housing vertical walls. One end of the shaft 62 projects externally of the housing 34 through a side wall thereof and connected to this end of the shaft is a heat motor 64 adapted to rotate the shaft to operate the dampers. The heat motor 64 may be of any well known suitable type or any other suitable actuator may be provided which will give a delayed or gradual opening of the dampers. The heat motor is connected by lead wires 65 to lead wires 66 which connect the room thermostat 15. to the motor l3 the thermostat l being connected'to the usual llO-volt line by main lead wires 61.

The operation of the herein described heating apparatus is as follows:

When the room thermostat l5 calls for heat,

' the motor l3 will start and operate the screw l2 to supply additional fuel to the retort and also the heat motor 64 will be energized. The motor l3 will drive the blower. l4 which will supply air to the duct 42 but at this time the dampers 6| operated by the slow acting heat motor 64 will be closed or substantially closed with the result that air pressure is built up in duct 42 from which duct air passes through inlets 45 and flows down the interior of the hollow screw shaft 32, keeping the same relatively cool.

and as previously mentioned aids in building up a pressure to resist the backing through the fuel supply duct 24. The delayed opening of the dampers prevents the blower l4 from extinguishing the fire which has been the principal objection to the use of slack or low grade fuel in the past and permits the addition of fuel to the retort to build up a fuel bed therein prior to utilizing the full capacity of the blower. Also at the start of the burner, air flows through the screw shaft 32 and protects the same against being burned out, the danger of which is particularly prevalent when there is a low fire bed in the retort. As the heat motor 64 gradually heats up, it gradually opens the dampers 6| to increase the supply of air to thefire. The motor I3 drives the agitators 54 through the gears 41, 48 and agitator shaft 50 which agitators keep the fuel stirred up and prevent the formation of clinkers in the retort.

The. air discharges from the hollow shaft from the outlet ports 60 up of smoke From the foregoing description it will now be seen that I have provided a new and improved stoker apparatus which will efliciently burn low grade fuel or slack. It will further be seen that I have provided a stoker having provisions to prevent burning out of the feed screw and one having provisions to prevent the formation of clinkers in the retort, with the result that substantially all of the heat may be obtained from low grade fuel. Moreover, I have provided a stoker apparatus in which the fuel pressure or pack in the supply duct may be readily adjusted, as desired. In addition, it will be seen that by "removing the bolts 42a the motor 13, blower I4 and duct 42- may be removed as a unitary structure from the apparatus.

While I have shown and described my invention in detail it is to be understood that the same is tobe limited only by the appended claims for many changes may be made without departing from. the spirit and scope of the invention.

What Iclaim is: 1

1. In a stoker heating apparatus, a retort; a feed screw extending into said retort and operable to deliver fuel thereto, means to drive said screw, said screw having'a hollow shaft extending within said retort and extending externally thereof in the opposite direction from the source of fuel supply, an air duct enclosing said shaft and leading to said retort, and a blower having its outlet connected to said 'air'duct and driven by said screw operating means, saidhollow shaft having an opening thereinto within said air duct for the passage of air through said hollow shaft'to cool the same. I

2. In a stoker heating apparatus, a retort, a feed screw extending into said retort and having a shaft extending externally of said retort, said shaft having an air inlet, and being hollow for flow of air therethrough to cool the shaft, duct means surrounding saidhollow shaft and providing a pressure chamber in which said inlet is located, said duct means leading to said retort to convey air thereto, blower means having an outlet'communicating with said chamber, normallyclosed damper means positioned intermediate said chamber and said retort to control flowthereto, means for automatically opening said damper and means for retarding. the opening of said normally-closed damper means for a predetermined delay after the starting of said blower and feed screw whereby to continuously supply a limited flow of air through said hollow shaft to said retort and cool the shaft until the fire bed is built up before opening said damper means.

3. In a stoker heating apparatus, a fuel burner having a conduit therethrough and having a fuel passage communicating with and extending upwardly from the conduit, a feed screw extendingv from a source of fuel supply through said conduit, said feed screw having a hollow shaft, means fuel supply.

FLOYD D. YARICK. 

